Technology for imaging the heart has advanced dramatically in recent years. In particular, real-time three-dimensional ultrasound (RT3D or 4D) has captured the imagination of cardiologists with its ability to obtain complete three-dimensional images of the heart over an entire cardiac cycle in just a few seconds of imaging. The complex cardiac wall motion and temporal information contained in these four-dimensional (3D + time) data sequences has the potential to greatly enhance clinical diagnoses of the heart. However, most cardiac examination centers still depend on 2D echocardiography, and the temporal information in the 4D cardiac imaging is often overlooked. The goal of this proposal is to utilize the wealth of information contained in 4D ultrasound. In particular, this proposal will focus on a common problem for which 4D cardiac imaging is ideally suited: measuring strain and cardiac torsion directly from 4D ultrasound. The aims of this proposal are: (1) Quantify errors of displacement and strain from optical flow on 4D ultrasound with respect to results obtained by sonomicrometry implanted in dog hearts;(2) Test the hypothesis that optical flow on 4D ultrasound can have clinically equivalent results on healthy volunteers (normal hearts) and diseased hearts compared to similar measures of strain obtained by MRI based methods;(3) Test the hypothesis that optical flow on 4D ultrasound has specific advantages in terms of performance over existing 2D based methods of strain estimation. The design of our method is based on optical flow to track myocardial motion in 4D ultrasound. Directional displacements and strains and cardiac torsion can be automatically derived from the 3D + time motion field estimated. In aims 1 and 2, specific displacements, strains, and torsion will be measured and compared to "gold standards" in quantitative evaluation studies. In aim 3, we will extensively compare the performance of 4D methods and 2D methods in estimating strain measures across a wide range of clinical echocardiography patient data sets. Once completed, the questions of why and when to best use 4D rather then 2D measures will be answered quantitatively. PUBLIC HEALTH RELEVANCE: The significance of the proposed work is that it will provide a novel and effective 3D strain and torsion measuring tool, allowing clinicians to routinely measure wall motion quantitatively and in real-time. In addition this research will provide cardiologists with improved screening tests for diabetic cardiomyopathy (and dyssynchrony) to help them determine those patients that may require more invasive and costly procedures such as heart catheterization from patients that can be safely spared such tests.